FIG. 11 is a plan view showing a main part of a conventional component mounting apparatus, FIG. 12 is a enlarged cross sectional view showing an image pickup unit of FIG. 11, and FIG. 13 is a schematic timing chart showing operation of each section in response to rotation of a rotary index table shown in FIG. 11. On a periphery of rotary index table 111 (hereinafter referred to as index table 111), suction nozzles 112 are installed.
A component feeding section 120 feeds each of a plurality of electronic component feeding units 121, storing various electronic components, to a lower side of a suction nozzle 112 moved to a suction position in accordance with control instructions. The suction nozzle 112 sucks an electronic component 113 from an electronic component feeding unit 121, and then rotation of the index table 111 moves the suction nozzle 112 to a recognition position (time t1 (FIG. 13)).
Once the suction nozzle 112 sucking and holding the electronic component 113 moves to the recognition position, with a lapse of vibration damping waiting time (time t1 to t2), LEDs 136 and 137 on a component image pickup unit 130 adequately illuminate the electronic component, so that first and second cameras 131 and 132 receive exposure from the electronic component via a mirror 133, a half mirror 134, and a further mirror 135 (time t2 to t3), and a taken image signal of the electronic component 113 is transmitted to an image processing unit based on NTSC method or the like (time t3 to t5). During transmission of the image signal to the image processing unit, the suction nozzle 112 that sucked the electronic component 113 starts to move to a placement position (time t4).
In a super high-speed component mounting apparatus, a series of processing operations including these operations is repeatedly executed in, for example, 80 ms tact. It is noted that the first and second cameras 131 and 132 in this example are both provided with, for example, about 250,000-pixel resolution, and each is equipped with an optical system different in terms of target components such that image pickup of a small component is performed by the first camera 131 while image pickup of a large component is performed by the second camera 132.
As for semiconductor devices, a degree of integration is incremental for implementation of a multifunction and the like, and large-size high-accuracy electronic components are increasing while smaller electronic components are also being manufactured. These circumstances are shown in an electronic component measurement table of FIG. 14. As shown in this table, electronic components include BGA (Ball grid Array) whose side length is about 32 mm, and there are also manufactured unshown larger-sized electronic components. It is noted that in FIG. 14, mini Tr denotes a mini-transistor, tantalum C denotes a tantalum capacitor, chip L denotes a large chip component that is larger than a chip component up to 0.6 to 3.2 mm, power Tr denotes a power transistor, aluminum electrolytic C denotes an aluminum electrolytic capacitor, SOJ refers to Small Outline J Lead Package, PLCC refers to Plastic Leaded Chip Carrier, SOP refers to Small Outline Package, CSP (0.5 p to 0.8 p) refers to Chip Sized Package having interelectrode pitches of 0.5 to 0.8 mm, and BGA (0.1 p−) refers to Ball Grid Array having interelectrode pitches of at least 0.1 mm. The numeral 0603 denotes a chip component having a size of 0.6 mm×0.3 mm, the numeral 2125 denotes a chip component having a size of 2.1 mm×2.5 mm, the numeral 3216 denotes a chip component having a size of 3.2 mm×1.6 mm, the □18 denotes a square chip component having a side length of 18 mm, and the □32 denotes a square chip component having a side length of 32 mm.
According to the conventional component mounting apparatus described with reference to FIGS. 11 and 12, if the first and second cameras 131 and 132 of a same kind having approximately 250,000-pixel resolution are each equipped with optical systems suitable in size for components subjected to image pickup, the first and second cameras 131 and 132 can at best perform good image pickup and image recognition of electronic components within respective ranges L1 and L2 as shown in the conventional method in FIG. 14 (up to a side length of about 18 mm).
This is, for example, because if the optical system mounted on the second camera is changed to enlarge the image pickup range, the small number of pixels thereof disturbs clear recognition of individual terminals (pins and balls) in an electronic component. An example thereof is shown in FIG. 15, wherein although an image EZ0 of an electronic component is obtained by the second camera as an image EZ1, an image of terminals thereof becomes unclear.
It is naturally considerable that as an extension of this conventional technology, a unit number of cameras is increased, for example, to three units, so that a third camera may be used for components having a side length of about at least 18 mm. However, this complicates structure and brings about high costs, and size of the image pickup unit itself becomes large and heavy, thereby causing an issue of susceptibility to influence of mechanical vibration.
Accordingly, for solving the above issue, it is an object of the present invention to provide a component recognition device and a method thereof as well as a component mounting apparatus and a method thereof enabling image pickup of small components to large components of approximately the same image pickup quality while maintaining good resolution for image recognition with use of image pickup units, for example two cameras, and enabling image processing while maintaining high-speed tact.